This quest took place on the second (of three) levels of the dungeon beneath the Tristram Cathedral in the BlizzCon 2008 demo. This simple quest might not be found in the final game, or might be changed then.

While exploring the dungeon, the player sees a gang of skeletons attacking a fallen NPC beyond a gate. Once the player rushes over and wipes out the skeletons (since that's what players do, in Diablo III) the NPC gets up and speaks. He gives his name and says he was leading a patrol when they were attacked and he was separated from his men. He asks the player for help in finding his troops and says he'll follow you.

A few screens away the player will come upon a group of NPC warriors battling a large mob of skeletons, zombies, and other undead. The NPC captain immediately starts shouting about how you must help his men, and the soldiers shout as well, when you get closer to them. There is usually a boss monster in the area, but with the NPCs to help occupy the monsters, the battle goes pretty quickly.

Once all of the demons are defeated, the NPC soldiers reunite and thank you for your help, before casting a town portal and vanishing through it. The player can not pass through their town portal, and is left alone in the dungeon.